So called "stop leak" compositions have long been used for stopping leaks in automobile cooling systems. Many of these compositions are aqueous suspensions of a particulate material that is entrained in the leak, thereby plugging it. Particulate materials that were used include linseed meal and metal flakes. However, these compositions are often not effective in completely stopping the leak, particularly under pressure, resulting in excessive loss of the coolant.
For many years stop leak compositions were improved by the addition of an asbestos fiber to the particulate material. However, the use of asbestos was not always effective and there are now known to be health and environmental problems associated with the use of asbestos.
It is also known to use asbestos fiber in an antifreeze composition to provide some leak stopping ability to the antifreeze.
In the above-cited Ser. No. 361,546 is disclosed a stop leak composition that is substantially more effective than the above-discussed prior art stopleak compositions in the stopping of leaks. Therein is disclosed a composition for the stopping of leaks in a leaky container, preferably a heat exchange system such as automobile cooling systems, which comprises a suspension in a liquid medium of a particulate material of a size and in an amount sufficient to become entrained in the leak, and fibrillated fiber coacting with the particulate material to seal the leak by an entwining action.
Typically stop leak compositions are supplied to the consumer in the form of a concentrate that is added to the fluid of the coolant system. In the case of a preferred stop leak of Ser. No. 361,546 above, a concentrate is formed comprising an aqueous suspension of a particulate material and a fibrillated fiber. This concentrate is then added by the consumer to the fluid of the cooling system, which is typically an antifreeze composition. The concentrate is then diluted by and dispersed throughout the cooling system to provide an effective amount of particulate material and fibrillated fiber to plug leaks in the cooling system.
An alternative method of supplying a stop leak to the consumer is to provide an antifreeze composition with leak stopping abilities. Thus, as the consumer periodically adds to or replaces the antifreeze in his automobile cooling system, a stop leak composition is added automatically. This method is generally not as desirable as the concentrate method above since the stop leak is applied universally, even to cooling systems without leaks. A consumer having a leak-free cooling system may not wish to have additional and unnecessary additives in the antifreeze used in his cooling system. Additionally it is uneconomical for the manufacturer to add a stop leak, when the antifreeze will primarily be used in systems that are free of leaks. Furthermore, providing an antifreeze to the consumer, which contains a stop leak, such as a stop leak of above-cited, Ser. No. 361,546, requires the addition of extra process steps and ingredients that add to the expense of manufacture but do not increase its effectiveness in most of the systems in which it used, since most cooling systems are leak-free. However, there are consumers, who, as a precautionary measure, wish to add a stop leak composition to their cooling system as they add antifreeze, even though their cooling system is free of leaks. In order to meet the need of these consumers, it would, therefore, be desirable to provide an antifreeze composition with a leak stopping ability in addition to providing the normal antifreeze not having leak stopping ability. However, considering the problems described above, such an antifreeze composition would have to be economical to manufacture and have a minimum amount of additional additives. Also the manufacture of such a stop leak antifreeze should be easily accomplished by a minimal alteration of existing manufacturing practices for making antifreeze. It would then be easy to quickly modify the manufacturing process to make either a stop leak containing or a stop leak free antifreeze.
It is, therefore, an object of the invention to provide an antifreeze composition with leak stopping ability.
It is also an object of the invention to provide an antifreeze composition with leak stopping ability without materially adding to the costs of making the antifreeze composition and with minimum of additional process steps in the manufacturing system.
It is further an object of the invention to provide an antifreeze composition with leak stopping ability that contains a minimum of additional additives.